904 Transmission Temporarily Disengages

[1966Belvert]

All,

I'm not a transmission guy and my attempts to search for this were unsuccessful, but I wanted to check with this esteemed group before taking my car to a transmission shop. I've been driving the Belvedere convertible quite a bit this summer and loving every minute of it. However, on 2 different occasions while driving it, the transmission disengaged for bit before kicking back in. In both instances, I was driving at very low speeds. After 15-30 seconds, the transmission would engage again. What would cause this?

Thanks in advance for any ideas. I just want some knowledge before I take it to the shop.

Steve

 

[RemCharger]

First thing is to check the hot trans fluid level idling in nuetral on a level surface.

 

[Lefty71]

Huh-oh

Hopefully this doesn't come into play. Maybe your fluid level is the critical error??

Dipstick for 904 Transmission

All, In preparation for a nice, long drive today, I checked all the fluids in my Belvedere. As I was putting the transmission dipstick back into place, the handle broke off. I've spent the last hour searching this site and using google. The only thing close to a stock solution that I found...

www.forbbodiesonly.com

 

[Geoff 2]

Fluid level &/or blocked filter.

 

[1966Belvert]

To update this thread, the fluid level is good and the filter has less than 1000 miles on it.

 

[Lefty71]

To update this thread, the fluid level is good and the filter has less than 1000 miles on it.

Kinda curious to know, what stick did you end up going with.... post #3....isnt that you??

 

[1966Belvert]

Kinda curious to know, what stick did you end up going with.... post #3....isnt that you??

I could not find an OEM version, so I went with one like this: Allstar Performance Locking Transmission Dipstick

 

[Geoff 2]

If the clutch & band material is wearing, it can quickly clog a filter. How did the old filter look?

 

[Wietse]

Since it was at low speed both events occurred, it can have something to do with the oil pressure.
Assuming you are right and the filter is clean and oil level is in specs.
This can indicate a bad pump which is not capable of putting out sufficient pressure at low rpm and (too) hot oil.
With a too low oil pressure the clamping force of the clutches and bands get too low and they will slip.
You can either do it yourself if you have the equipment or let a transmission shop check the line pressure of the transmission with oil at operating temperature.
Original the pressure should be around 54-60 psi at idle, if it is lower than that can be caused by a worn out pump.